We've confirmed that all systems are back to normal with no customer impact as of 8/25, 18:00 UTC. Our logs show the incident started on 8/25, 16:30 UTC and that during the incident customers using Log Analytics in USGov Virginia may have received failure notifications - such as HTTP 502 Gateway Timeout or 503 Service Unavailable - when performing log search operations for data access. Alerting may have also been delayed. Tiles and blades may also have failed to load and display data.
Preliminary Root Cause: Engineers determined that instances of a backend service became unhealthy, preventing these requests from completing.
Mitigation: Engineers performed a manual restart of a backend service to mitigate the issue
We understand that customers rely on Azure Log Analytics as a critical service and apologize for any impact this incident caused.
-Azure Monitor SRE
Initial Update: Sunday, 25 August 2019 17:43 UTC
We are aware of issues within Log Analytics and are actively investigating. Some customers may experience Data Access issues and Alerts may also be impacted in US national Cloud.
Work Around: None
Next Update: Before 08/25 20:00 UTC
We are working hard to resolve this issue and apologize for any inconvenience. -Azure Monitor SRE